High efficiency unit filter assembly

Claim 1

A FILTER COMPRISING AN OPEN-ENDED HOUSING HAVING AN UPSTREAM DIRTY GAS INLET AND A DOWNSTREAM CLEAN GAS OUTLET; SAID HOUSING HAVING DISPOSED THEREIN A STRIP OF GLASS FIBER FILTER MEDIUM FOLDED UPON ITSELF AT LONGITUDINALLY SPACED INTERVALS TO PROVIDE A PLURALITY OF STACKED PLEATS WITHING SAID HOUSING EXTENDING BETWEEN OPPOSITE WALLS THEREOF AND HAVING SUCCESSIVELY ALTERNATING PLEAT FOLDTURNS; A PLURALITY OF CORRUGATED, THIN METALLIC FOIL SPACER MEMBERS DISPOSED WITHIN AND EXTENDING ALONG THE LENGTHS OF SAID PLEATS TO SPACE THE SAME; SAID SPACER MEMBERS HAVING U-SHAPED CHANNEL MEMBERS EXTENDING ACROSS AND ENGAGING THE TRANSVERSE EDGES OF THE SPACER MEMBERS ADJACENT THE PLEAT FOLD-TURNS TO ROUND OFF SAID EDGES TO MINIMIZE WEAR AND TEAR OF SAID FOLD-TURNS; ALTERNATE SPACER MEMBERS HAVING A BREADTH GREATER THAN THE BREADTH OF A SPACED PLEAT IMMEDIATELY ADJACENT THERETO WITH THE LONGITUDINAL SIDE EDGES OF SAID ALTERNATE SPACER MEMBERS BEING FOLDED UPON THEMSELVES TO ENGAGE THE LONGITUDINAL SIDE EDGES OF AN IMMEDIATELY ADJACENT PLEAT THEREBETWEEN TO FORM LONGITUDINAL EDGE SEALS THEREALONG; AND A SEALANT OF ADHESIVE CEMENT SURROUNDING THE UPSTREAM PERIMETER OF SAID STACKED PLEATS TO SEAL SAID UPSTREAM PERIMETER WITH THE UPSTREAM INNER WALL OF SAID SURROUNDING HOUSING, THE DOWNSTREAM PERIMETER OF SAID STACKED PLEATS FLOATING RELATIVE SAID SURROUNDING HOUSING.